1、66 Frequency band Function and type of earth station (MHz) 4855212 053b595 b4 Interfering signal power (dBW) in the reference bandwidth to be exceeded for no more than 20% of the time Interfering signal power (dBW) in the reference bandwidth to be exceeded for no more than p% of the time Rec. ITU-R
2、SA.1160-2 Direct data readout High gain antenna Data dissemination Low gain antenna RECOMMENDATION ITU-R SA. 1 160-2 -153.8 dBW per 2.6 MHz -167.5 dBW per 4 kHz -148.6 dBW per 2.6 MHz p = 0.025 -160.4 dBW per 4 kHz p = 0.025 INTERFERENCE CRITERIA FOR DATA DISSEMINATION AND DIRECT DATA READOUT SYSTEM
3、S IN THE EARTH EXPLORATION-SATELLITE AND METEOROLOGICAL-SATELLITE SERVICES USING SATELLITES IN THE GEOSTATIONARY ORBIT (Question ITU-R 141/7) Data dissemination High gain antenna Command data acquisition (CDA) station High resolution data CDA station WEFAX data (1995-1997-1999) -153.4 dBW per 2.1 1
4、MHz -136.7 dBW per 2.11 MHz -148.1 dBW per 2.1 1 MHz p = 0.025 -133.4 dBWper2.11 MHz p = 0.025 -140.7 dBW per 4 kHz p = 0.025 -147.8 dBW per 4 kHz The ITU Radiocommunication Assembly, I I 25 500-27 O00 space-to-Earth Direct data readout -131.7 dBW per 10 MHz considering that interference criteria ar
5、e needed to ensure that systems can be designed to achieve adequate performance in that interference criteria may be determined using the methodology described in Recommendation that interference criteria assist in the development of criteria for sharing bands among systems, including those that sys
6、tems in the Earth exploration-satellite service (EESS) and meteorological-satellite (MetSat) service that Annex 1 presents the parameters of representative systems that provide the basis for permissible levels of a) the presence of interference; b) ITU-R SA. 1022 and the performance objectives liste
7、d in Recommendation ITU-R SA. 1 159; c) operating in other services; d) must speci3 interference thresholds at levels greater than or equal to the permissible levels; e) interference for pertinent transmissions in the EESS and MetSat service, -1 16.3 dBW per 10 MHz D = 0.25 recommends that the inter
8、ference levels specified in Table 1 be used as the permissible total levels of interfering signai 1 power at the antenna output of stations operating in the EESS and MetSat service. 1 670-1 7 1 O space-to-Earth 2025-2110 Earth-to-s pace . Link parameter Down-link e.i.r.p. = 4855212 053b5b 520 Value
9、Notes 16.1 dBW Rec. ITU-R SA.1160-2 67 Down-link loss Down-link G/T Down-link C/NO Data rate NOTE i -The interfering signal powers (dBW) in the reference bandwidths are specified for reception at elevation angles 2 3. NOTE 2 - The total interfering signal power level that may be exceeded for no more
10、 than x% of the time, where x is less than 20% but greater than the specified short-term time percentage (p% of the time), may be determined by interpolation between the specified values using a logarithmic scale (base 1 O) for percentage of time and a linear scale for interfering signal power densi
11、ty (dB). NOTE 3 - The sharing criteria can be expressed as permissible power flux-densities into the main beam of the receive antenna by subtracting 10 log(G h2/4x) from the value given in Table 1, where G is the receive antenna gain and h is the wavelength. NOTE 4 - Although the interference criter
12、ia are based on the systems described in Annex i, the interference criteria apply to all systems that operate in the subject frequency bands and which provide the specified service functions. 190.1 dB 24.4 dB(K-) 79.0 dB/Hz 2.6 Mbit/s Free-space, polarization, and antenna pointing ANNEX 1 Required C
13、/NO - . Margin Receive antenna gain Basis for interference criteria 78.1 dB/Hz BER= 1 x lo4 2.2 dB implementation loss 1 dB modulation loss 0.9 dB Long-term and short-term 45.1 dBi This Annex presents the parameters used as inputs to the methodology of Recommendation ITU-R SA. 1022 to determine the
14、interference criteria for data dissemination and direct readout systems. Receiver noise density Interference Long-term criteria Short-term 1 Direct readout systems Table 2 develops these criteria for direct readout systems, in which all of the interference enters the receiving station directly, and
15、none is received at the station via the satellite that originates the data. The interference criteria can be expressed as permissible power flux-densities into the main beam of the receive antenna by subtracting 10 log(G h2/4n) fiom the values giv& in Table 2, where G is the receive antenna gain and
16、 h is the wavelength. -207.9 dB(W/HZ) -153.8 dB(W/2.6 MHz) -148.6 dB(W/2.6 MHz) q = 1/3 and M, = 1.2 dB q = 1 and Mmin = 1.2 dB TABLE 2 Direct data readout system performance used as a basis for interference criteria of stations operating with satellites in geostationary orbit a) Frequency band 1 67
17、0-1 710 MHz c Link parameter Down-link e.Lr.p. 68 Value Notes 50.8 dBW YB55212 0536577 467 Rec. ITU-R SA.1160-2 TABLE 2 (continued) Long-term Short-term Down-link loss b) Frequency band 25.5-27.0 GHz 213.2 dB 220.3 dB Free-space, polarization, and antenna pointing 7.1 dB excess path loss Down-link G
18、/T Down-link C/NO Long-term Short-term 3 1.6 dB(K-) 97.8 dBIHz 90.7 dB/Hz Data rate Required C/NO Long-term Short-term Margin Receive antenna gain 15 Mbit/s 83.8 dB/Hz BER = 1 x 0.5 dB implementation loss 1 dB modulation loss 14.0 dB 6.9 dB 60.1 dBi RecGr noise density- I -200.1 dB(W/Hz) I Interfere
19、nce criteria Long-term -131.7 dB(W/lO MHz) Short-term -1 16.3 dB(W/10 MHz) q = 113 and M, = 1.2 dB q = 1 and M, = 1.2 dB 2 Data dissemination systems Dissemination of high-resolution processed data and lower-resolution WEFAX data is affected by interference received at the station via the satellite
20、as well as by interference transmitted directly into the station in the 1 670-1 710 MHz band. The high-resolution processed data and the WFAX data are up-linked to the satellite in the 2 025-2 1 10 MHz band, and relayed, along with interfering signals entering the satellite in the same band, to the
21、Earth station receivers via fixed-gain satellite transponders. The up-link and down-link carrier-to-noise plus interference density ratios are respectively: and where: Io1 and 102 : interference densities transmitted into the satellite and station receivers Ti and T2 : system noise temperatures of t
22、he satellite and station receivers k: Boltzmanns constant. D 4855232 0536598 3T3 Rec. ITU-R SA.1160-2 69 The composite carrier-to-noise plus interference density ratio is: From Recommendation ITU-R SA. 1022 this can also be written: where: M: interference-free margin 4: C/NO : action of the interfer
23、ence-fiee margin that the interference is allowed to consume composite carrier-to-noise density ratio given by: From the foregoing equations: Assume that the up-link and down-link interference are allocated so that a fraction p of the interference received at the earth station is received via the sa
24、tellite, and that a fraction 1 -p is transmitted directly into the station, It is desirable for p to be near 1/2 in order to provide a reasonable balance in the interference allocated to the uplink and to the down-link. For a fixed-gain transponder it can be shown that: so that: -1 ,P=l+-+( 1 Io1 P
25、kT1 )down Accordingly, the permissible up-link interference density becomes: where, according to Recommendation ITU-R SA.1022, Mmin is the smallest interference-free margin for which only a fraction q of the margin is consumed by the interference. Correspondingly, the permissible down-link interfere
26、nce density is: Tables 3 and 4 summarize the calculation of Io, and 102 for high-resolution and WEFAX data respectively, assuming that p = 112, q = 113, and Mmi, = 1.2 dB for long-term interference, and that p = 1/2, q = 1, and Mmin = 1.2 dB for short-term interference. The interference criteria can
27、 be expressed as permissible power flux-densities into the main beam of the receive antenna by subtracting 10 log(G h2/4.n) from the values given in Tables 3 and 4, where G is the receive antenna gain and h is the wavelength. . Link parameter Up-link e.i.r.p. 70 Value Notes 72.1 dBW Rec. ITU-R SA.11
28、60-2 9 i .5 dB/Hz 23.8 dBW 190.1 dB TABLE 3 Performance analysis used as a basis for interference criteria of high-resolution data dissemination systems using geostationary satellites Free-space, polarization, and antenna pointing Data rate Required C/No Up-link loss Up-link G/T 2.1 1 Mbitls 75.9 dB
29、/Hz BER = 1 x 10“ 1.9 dB implementation loss Up-link C/NO Down-link e.i.r.p. Margin Up-link receive antenna gain Up-link noise density Down-link loss i .4 dB 9.5 dBi -20 1.6 dB(W/Hz) T= 500 K Down-link G/T Down-link C/NO Up-link interference criterion Composite C/NO Long-term -136.7 dB(W/2.11 MHz) q
30、= 113 Short-term -133.4 dB(W/2.11 MHz) 41 191.7 dB I Free-space, polarization, and antenna pointing I Down-link receive antenna gain Down-link noise density -17.5 dB(K-l) I Post-launch measurement 39.5 dBi -204.3 dB(W/Hz) T= 269 K Down-link interference criterion 15.2 dB(K-I) 71.5 dB/Hz 77.3 dB/Hz L
31、ong-term -153.4 dB(W/2.11 MHz) q= 1/3 Short-term -148.1 dB(W/2.I 1 MHz) q= 1 Link parameter Up-link e.i.r.p. Up-link loss Value Notes 66.7 dBW 191.7 dB Free-space, polarization, and antenna pointing Up-link G/T Uplink C/NO Down-link e.i.r.p. -17.5 dB(K-I) Post-launch measurement 86.1 dB/Hz 24.3 dBW
32、TABLE 4 Down-link loss Down-link G/T 189.6 dB Free-space and polarization -0.3 dB(K-l) Down-link C/NO 63.0 dBNz = ri855212 053bb00 881 = Link parameter Composite C/& IF bandwidth Required C/& Margin Up-link receive antenna gain Up-link noise density Rec. ITU-R SA. 1160-2 TABLE 4(en) Value Notes 63.0
33、 dB/Hz 50 kHz 57.0 dB/Hz 6.0 dB 9.5 dBi -20 1.6 dB( W/Hz) 10 dB FM threshold T= 500 K 71 Up-link interference criterion Long-term -147.8 dB(W/4 Hz) q= 1/3 Short-term -140.7 dB(W/4 kHz) q= 1 Down-link receive antenna gain Down-link noise density 30.1 dBi -198.2 dB(W/Hz) T= 1 100 K Down-1 ink interference criterion Long-term -167.5 dB(W/4 Hz) q= 1/3 Short-term -160.4 dB(W/4 kHz) q= 1
